First gear slips into neutral - '85 XJ700

Hi all,

So there are lots of things that I want to cross off my list this season. You know, the usual. Valve clearance adjustment and carb sync at the CNY Carb Clinic, replace the front fork seals, possibly replace the clutch - all nice things. In general the bike runs great.

There is one thing, though, that lurks in the back of my mind. When I engine brake in first gear, sometimes I'll suddenly slip into neutral. This happened twice last season, and a handful of times this season so far. It typically happens only when engine speed is above 5500 rpm, although it has happened once as low as 4000. It's more prone to happening when there is a passenger riding with me.

I combat this problem by using the rear brake and slightly rolling the throttle while engine braking in first. It ultimately makes for a much smoother reduction in engine speed, and I suppose reduces the rearward force on first gear?

Anyone out there who knows what this is? How can I fix it? My hope is that this issue can wait a little while before it absolutely needs to be addressed, as I assume it is transmission related, and therefore expensive. I'm in it for the long haul on this one, love the bike - just want to plan out any big expense as best as possible.

Thanks!

Elliott

 

There are three things that come to mind.

1. The shift selector is not rotating fully, so first gear is not completely engaged. Remove the shift cover and inspect the shift drum to shift shaft mechanism for wear or a weak spring.

2. You have a bent shift fork. This requires splitting the cases to remedy, but is not terrably expensive to do.

2. The dogs are worn, allowing the gear to get pushed out of place under load. Again you have to split the cases to remedy this. The gear dogs can be backcut to provide full engagement. This is not terribly hard, or expensive, but does require some care and patience.

 

Thanks for the information k-moe, honestly makes it much more manageable now as opposed to some mysterious negative dollar sign hanging over the bike.

I should probably open it up and take a look. Here's another thought - do you think that a bent shift fork would also cause "chatter" during a downshift from 2nd to 1st? From time to time if I just coast to a red light with the clutch engaged, and attempt to shift down from 2nd into 1st I get nothing but chatter - it's clearly audible and the shift lever rapidly bounces under my foot. Lasts half a second or so I would guess.

 

I have had the same problem minus the chatter. I'd like to know what you find out.